1. Technical Field
The present invention relates to a power supply stabilizing circuit, an electronic device, and a test apparatus. In particular, the present invention relates to a power supply stabilizing circuit that stabilizes the power supply voltage supplied to an operation circuit of the electronic device, an electronic device that houses the power supply stabilizing circuit, and a test apparatus that uses the power supply stabilizing circuit.
2. Related Art
A known technique for stabilizing the power supply voltage supplied to the operation circuit of an electronic device such as a semiconductor circuit involves connecting a bypass capacitor to the power supply wiring, as described in Patent Document 1. Generally, the bypass capacitor is provided outside of the chip of the electronic device between a ground potential and the power supply line that supplies the electronic device with power.
The change in the current flowing through the power supply line can then be restricted by supplying the electronic device, via the power supply input terminals, with current corresponding to the change in the current consumed by the electronic device. In this way, the change in the power supply voltage due to current fluctuation can be suppressed. The capacitance of the bypass capacitor is usually between tens of nF and several μF.    Patent Document 1: Japanese Patent Application Publication No. H07-333249
However, in the wiring from the power supply input terminals of the electronic device to the operation circuit, the power supply voltage changes according to the change in the current consumed by the operation circuit. This power supply voltage change cannot be compensated for by a bypass capacitor provided outside the chip of the electronic device.
One technique for solving this problem involves providing a similar bypass capacitor within the chip of the electronic device. The gate capacitance of a transistor can be used to realize the capacitor disposed in the chip of the electronic device. However, since the gate capacitance of a single transistor is around tens of fF, an extremely high number of elements must be formed to provide the bypass capacitor within the chip.
Furthermore, when using the bypass capacitor to compensate the power supply voltage, the frequency characteristics of the power supply voltage compensation are determined by the capacitance of the bypass capacitor. Therefore, it is difficult to compensate for the change in the power supply voltage over a wide range using a single bypass capacitor.